Loggerhead shrike description

The only member of the Laniidae family (true shrikes) to occur exclusively in North America (4), the loggerhead shrike (Lanius ludovicianus) is unusual among songbirds for its predatory behaviour. Like other Lanius shrikes, it has a stout, hooked bill for killing prey, and is known for its habit of impaling its victims on sharp objects. This behaviour has earned Lanius species the name of “butcher birds” (3)(4)(5)(6).

The loggerhead shrike is a medium-sized shrike species (2)(3)(6), named for its proportionately large head (3)(4). Both the male and female have a grey back, forehead and crown, a distinctive black mask across the face, and a whitish throat and underparts, which are sometimes tinged grey. Some individuals show faint dark barring on the chest. The wings are black, with a conspicuous white patch and with white edges to the scapulars (shoulder feathers) which form a white “V” across the back. The loggerhead shrike’s tail is of medium length and is black with white outer feathers. The legs, feet and hooked bill are also black (2)(3)(4)(6).

Although similar in appearance to the male, the female loggerhead shrike is smaller and often has faint markings on the breast, slightly browner rather than bluish-grey upperparts, and a less extensive face mask (2)(4)(6). The juvenile resembles the adult, but is a paler brownish-grey, with fine barring above and below, a browner face mask, a buffy bar on the wing and a pale base to the lower beak (2)(3)(4)(6).

The loggerhead shrike varies in size and appearance across its range. Around 7 to 11 different subspecies have been described, but these overlap somewhat (2)(4)(6). The adult loggerhead shrike can be distinguished from the only other shrike in its range, the great grey shrike or northern shrike (Lanius excubitor), by its smaller size, shorter bill, larger face mask and less extensive barring on the chest (2)(3)(4)(6).

The song of the loggerhead shrike consists of short trills or combinations of clear, almost metallic notes, and it also gives a great variety of harsh calls (2)(3)(4)(6).

Related species

Loggerhead shrike biology

The diet of this small predatory bird consists mainly of insects, but it also takes spiders, snails, crabs, crayfish, and small vertebrates such as lizards, amphibians, birds, rodents and sometimes fish. The loggerhead shrike will also feed on carrion and roadkill (2)(4)(5)(6). Hunting usually takes place from an exposed perch, from which the loggerhead shrike sits and watches for potential prey (2)(3)(4)(5)(6). It may also hover when foraging (2)(4)(6). Most prey is caught on the ground, but insects may also be captured in the air (2)(6).

Unlike birds of prey, the loggerhead shrike does not have strong feet and talons. Instead, it relies on its sharp, hooked bill to kill its prey, with small vertebrates usually being dispatched with a bite to the back of the neck. Smaller prey may be eaten immediately, but larger items are carried back to a perch, sometimes held in the feet. The victim is often then impaled on a sharp object such as a thorn or barbed wire, or wedged into the fork of a tree, before being ripped apart (3)(4)(5)(6). The loggerhead shrike also stores food by impaling it, particularly in winter when food is scarce, or during the breeding season when its energy demands are greater (4)(5)(6). Noxious prey is often impaled and left for several days, which may allow its poisons to degrade before it is eaten (4).

The loggerhead shrike breeds relatively early in the year, from about February to July. Breeding usually occurs slightly later in mountainous areas and in the northern parts of its range (2)(4)(6). The nest of the loggerhead shrike is usually located in a thorny tree or shrub and is built mainly by the female. It consists of a bulky cup of sticks, grass and bark strips, and is lined with rootlets, plant fibres, moss, grass, animal hair, feathers, and sometimes man-made materials like paper or cloth (2)(4)(6).

The female loggerhead shrike incubates the clutch of 1 to 9 eggs for about 15 to 17 days, during which time she is fed by the male (2)(3)(4)(5)(6). Both adults feed the chicks, which leave the nest at around 16 to 21 days old (2)(4)(5)(6). The young loggerhead shrikes become independent after three to four weeks (2)(5)(6), but sometimes stay with the adults for up to three months (2)(6). The loggerhead shrike first breeds at a year old (4)(6), and may live for three to four years (6). In southern parts of its range, the loggerhead shrike may raise two or even three broods a year (2)(4)(6).

Loggerhead shrike range

The loggerhead shrike has a widespread distribution across North America, from southern Canada, through the United States to Mexico, where it reaches as far south as Oaxaca (2)(3)(4)(6)(7). Northern populations are migratory, moving south for the winter, but most southern populations remain on the breeding grounds year-round (2)(4)(6). This species is also occasionally recorded in Guatemala, Bermuda and the Bahamas (4)(6)(7).

Of the loggerhead shrike’s subspecies, Lanius ludovicianus mearnsi is restricted to the island of San Clemente, off the coast of southern California, while Lanius ludovicianus anthonyi is restricted to the California Channel Islands of Santa Rosa, Santa Cruz and Santa Catalina (2)(4).

Species with a similar range

Loggerhead shrike habitat

The loggerhead shrike occurs in open and semi-open areas, typically with short vegetation and scattered trees or bushes (2)(4)(5)(6). It inhabits a wide range of habitat types, including pastures, open woodland, agricultural fields, semi-desert, scrubland, wooded savanna, old orchards, mowed roadsides, parks, and even golf courses and cemeteries (2)(4)(6).

Important features of the loggerhead shrike’s habitat include suitable perching sites, such as isolated trees, bushes or fences, which can be used as lookout posts when hunting (5)(6). It also requires thorny trees or barbed wire fences for impaling prey (2).

Loggerhead shrike status

Loggerhead shrike threats

Although it is widespread and not currently considered globally threatened, the loggerhead shrike has undergone a significant decline in recent decades and has disappeared from some areas, particularly in the northeast of its range (2)(4)(5)(6)(7)(8).

The reasons for the loggerhead shrike’s decline are not well understood, but it is likely to face a number of threats, including habitat alteration and the effects of pesticides. In particular, loggerhead shrike populations may be affected by land-use changes, such as the conversion of pastures to cropland, the removal of hedgerows, and urbanisation (4)(6)(8)(9)(10)(11). This species also has a habit of perching along roadsides and it typically flies low to the ground, making collisions with vehicles a concern (4)(6)(8)(9)(10).

In Canada, the loggerhead shrike is listed as either ‘Threatened’ or ‘Endangered’ by the Committee on the Status of Endangered Wildlife in Canada (COSEWIC) (12). The subspeciesLanius ludovicianus migrans (eastern loggerhead shrike) is particularly endangered, having been lost from almost all of its former Canadian range (2)(9)(10).

The San Clemente loggerhead shrike (L. l. mearnsi) is also highly threatened, and is listed as ‘Endangered’ by the U.S. Fish and Wildlife Service (13). Its entire population is confined to a single island and dipped to a low of just 14 individuals in the early 1990s (2)(4)(6)(14). The main threats to this subspecies are predation by native and introduced predators, and habitat loss due to overgrazing by feral livestock (4)(6)(15).

Loggerhead shrike conservation

A number of conservation projects are underway for the most threatened populations of the loggerhead shrike. In Canada, the Eastern Loggerhead Shrike Recovery Program is working to save the subspeciesL. l. migrans, by restoring its habitat, monitoring its populations, and undertaking a captive breeding programme with the aim of releasing captive-bred individuals into the wild (9)(10). The results have so far been positive, with the wild population now increasing (10).

The San Clemente loggerhead shrike (L. l. mearnsi) is listed in a recovery plan for the species of the California Channel Islands (16), and an active recovery programme is underway for this subspecies. Feral herbivores have been removed from San Clemente Island to allow the natural vegetation to re-grow, and captive-bred loggerhead shrikes are being released into the wild (4)(14)(15). Efforts are also being made to control predators such as cats, although these still remain a threat (4)(15). As a result of these measures, the wild population of the San Clemente loggerhead shrike has increased to around 46 pairs plus 100 juveniles in 2009 (15).

Other conservation measures in place for the loggerhead shrike include the use of road signs to encourage drivers to slow down in areas where collisions with vehicles are a threat (9)(10). Further recommended actions for this species include the preservation of suitable habitat, the restoration of hedgerows and management of roadside habitat, and a reduction in the use of pesticides (2)(4)(8)(11). It will also be important to clarify the causes of the loggerhead shrike’s decline, and to undertake further studies into its migration routes, wintering areas and dietary needs (2)(4).

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